1. Field of the Invention
The present invention relates to a manually loaded, platen-roll-driven envelope feeder for serially feeding envelopes from a loading station to a printing station of a conventional printer where the envelopes are addressed, and for removing addressed envelopes from the printing station for release at a discharge station, with the printing, discharge and loading stations being located at vertically spaced positions along a front side of the feeder, with the discharge station being above the printing station, and with the loading station being above the discharge station.
2. Prior Art
There has long been a need for a simple and inexpensive, yet reliable apparatus for sequentially feeding envelopes to and from the printing station of a printer for addressing. With the advent of automatic typewriters and programmable printers that can operate unattended, a number of proposals have been made to provide relatively complex, fully automated systems for feeding envelopes in a serial manner to and from a printing station of a printer.
One prior proposal has been to utilize continuous-form envelopes rather than individual envelopes, whereby an uninterrupted web of serially connected envelopes is fed around the platen roll of a printer. This proposal has suffered from several drawbacks including the dramatically increased cost of continuous-form envelopes.
Another proposal has been to provide a feeding unit in the form of an appliance that is positioned adjacent to the platen roll of a printer for sequentially introducing envelopes to the printer at one side of the printer's platen roll, and for removing printed envelopes from the other side of the platen roll. This proposal lacks a positive-feed transport system for reliably conveying envelopes around the platen roll for precise positioning at a printing station, whereby it is not uncommon for envelopes to misfeed or fail to feed around the platen roll of the printer.
Still another proposal has called for the use of a relatively complex feeder unit which mechanically interconnects with the platen roll of a printer, and which has a number of power-operated, electrically controlled components that are caused to cycle through a staged feeding sequence in response to rotation of the platen roll. By this arrangement, envelopes are fed from a supply hopper through a printing station to a receiving hopper, and a programmable printer initiates the printing of a new address at the exact time when the feeder has properly positioned a new envelope in the printing station, whereby unattended automatic addressing of a large number of envelopes can be reliably effected.
The apparatus that is used to implement this latter proposal makes use of a plurality of individual feeding mechanisms to effect a multi-step, stage by stage feeding of envelopes from a supply hopper through a printing station to a receiving hopper. A dispensing mechanism supports the supply stack of envelopes and dispenses them one at a time from the bottom of the stack. A positioning mechanism receives envelopes from the dispensing mechanism and positions them one at a time along the path of travel of a pair of transport belts. A transport mechanism includes the transport belts and other structure for defining the travel path such that the travel path extends around the printer's platen roll. The belts have lugs which engage the trailing edge of an envelope to be fed, and positively feed the envelope along the travel path to and from the printing station. Additional feeding structure cooperates with the transport belts to move addressed envelopes from the printing station to the receiving hopper.
A drawback of the foregoing proposals is that they do not address the need which remains for a very simple and inexpensive, manually loaded, envelope feeder for sequentially delivering envelopes to and from a printing station of a conventional printer such as a typewriter.